Gloss or effect pigments are applied to various industrial fields, particularly, to automobiles, decorative coatings, plastics, paints, printing inks, and cosmetic mixtures.
Gloss pigments based on transparent platelet-shaped substrates free from “high-contrast” metallic gloss are prepared by coating a highly refractive metal oxide layer (for example, TiO2) and, optionally, an absorption layer onto mica platelets. These pigments exhibit a specific interference color depending on thickness of a TiO2 layer when observed in a flat state, and the interference color gradually becomes fainter and finally changes to gray or black as viewing angle is increasingly tilted. Here, deterioration in the degree of color saturation is observed, despite no change in the interference color.
Recently, a gloss pigment, which is based on glass platelets or mica particles coated with an opaque metal layer and alternate SiO2 and TiO2 layers, has been developed.
However, in some cases, existing multilayer pigments known in the art are prepared from layer materials, which substantially block transmission of light or allow transmission of only a small amount of light, and thus can be combined with absorption pigments only in an extremely limited range upon coating. In addition, since the interference color of such pigments significantly depends on viewing angle, such pigments are not suited to most purposes. Further, in some cases, it is extremely difficult to prepare or recover such pigments.
In the related art, Korean Patent Publication No. 10-2008-0017485 (publication date: 2008. 02. 26) discloses an interference pigment based on glass flakes.